Token and Phrase Spell Correction Job - Lucidworks documentation

Detect misspellings in queries or documents using the numbers of occurrences of words and phrases.

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Default job name	`COLLECTION_NAME_spell_correction`
Input	Raw signals (the `COLLECTION_NAME_signals` collection by default)
Output	Synonyms (the `COLLECTION_NAME_query_rewrite_staging` collection by default)

	query	count_i	type	timstamp_tdt	user_id	doc_id	session_id	fusion_query_id
Required signals fields:	✅	✅	✅

This job extracts tail tokens (one word) and phrases (two words) and finds similarly-spelled head tokens and phrases. For example, if two queries are spelled similarly, but one leads to a lot of traffic (head) and the other leads to a little or zero traffic (tail), then it is likely that the tail query is misspelled and the head query is its correction. If several matching head tokens are found for each tail token, the job can pick the best correction using multiple configurable criteria. You can review, edit, deploy, or delete output from this job using the Query Rewriting UI.

Misspelled terms are completely replaced by their corrected terms. If you want to expand the query to include all alternative terms, set the synonyms to bi-directional. See Synonym Detection for more information.

This job’s output, and output from the Phrase Extraction job, can be used as input for the Synonym Detection job. Solr treats spelling corrections as synonyms. See the blog post Multi-Word Synonyms: Solr Adds Query-Time Support for more details.

1. Create a job

Create a Token and Phrase Spell Correction job in the Jobs Manager. How to create a new job

In the Fusion workspace, navigate to > Jobs.
Click Add and select the job type Token and phrase spell correction. The New Job Configuration panel appears.

2. Configure the job

Use the information in this section to configure the Token and Phrase Spell Correction job.

Required configuration

The configuration must specify:

Spark Job ID. Used in the API to reference the job. Maximum 63 alphabetic characters, hyphen (-), and underscore (_).
INPUT COLLECTION. The trainingCollection parameter that can contain signal data or non-signal data. For signal data, select Input is Signal Data (signalDataIndicator). Signals can be raw (from the _signals collection) aggregated (from the _signals_aggr collection).
INPUT FIELD. The fieldToVectorize parameter.
COUNT FIELD For example, if signal data follows the default Fusion setup, then count_i is the field that records the count of raw signals and aggr_count_i is the field that records the count after aggregation.

See Configuration properties for more information.

Event types

The spell correction job lets you analyze query performance based on two different events:

The main event (the Main Event Type/mainType parameter)
The filtering/secondary event (the Filtering Event Type/filterType parameter)
If you only have one event type, leave this parameter empty.

For example, if you specify the main event type to be click with a minimum count of 0 and the filtering event type to be query with a minimum count of 20, then the job:

Filters on the queries that get searched at least 20 times.
Checks among those popular queries to determine which ones didn’t get clicked at all, or were only clicked a few times.

Spell check documents

If you unselect the Input is Signal Data checkbox to indicate finding misspellings from content documents rather than signals, then you do not need to specify the following parameters:

Count Field
Main Event Field
Filtering Event Type
Field Name of Signal Type
Minimum Main Event Count
Minimum Filtering Event Count

Use a custom dictionary

You can upload a custom dictionary of terms that are specific to your data, and specify it using the Dictionary Collection (dictionaryCollection) and Dictionary Field (dictionaryField) parameters. For example, in an e-commerce use case, you can use the catalog terms as the custom dictionary by specifying the product catalog collection as the dictionary collection and the product description field as the dictionary field.

Example configuration

This is an example configuration:

When you have configured the job, click Save to save the configuration.

3. Run the job

If you are finding spelling corrections in aggregated data, you need to run an aggregation job before running the Token and Phrase Spelling Correction job. You do not need to run a Head/Tail Analysis job. The Token and Phrase Spell Correction job does the head/tail processing it requires.

How to run the job

In the Fusion workspace, navigate to > Jobs.
Select the job from the job list.
Click Run.
Click Start.

4. Analyze job output

After the job finishes, misspellings and corrections are output into the query_rewrite_staging collection by default; you can change this by setting the outputCollection. An example record is as follows:

correction_s                  laptop battery
mis_string_len_i              14
misspelling_s                 laptop baytery
aggr_job_id_s                 162fcf94b20T3704c333
score                         1
collation_check_s             token correction included
corCount_misCount_ratio_d     2095
sound_match_b                 true
id                            bf79c43b-fc6d-43a7-931e-185fdac5b624
aggr_type_s                   tokenPhraseSpellCorrection
aggr_id_s                     ecom_spell_check
correction_types_s            phrase => phrase
cor_count_i                   68648960
suggested_correction_s        baytery=>battery
cor_string_len_i              14
token_wise_correction_s       baytery=>battery
cor_token_size_i              2
edit_dist_i                   1
timestamp_tdt                 2018-04-25T13:23:40.728Z
mis_count_i                   32768
lastChar_match_b              true
mis_token_size_i              2
token_corr_for_phrase_cnt_i   1

For easy evaluation, you can export the result output to a CSV file.

5. Use spell correction results

You can use the resulting corrections in various ways. For example:

Put misspellings into the synonym list to perform auto-correction.
Help evaluate and guide the Solr spellcheck configuration.
Put misspellings into typeahead or autosuggest lists.
Perform document cleansing (for example, clean a product catalog or medical records) by mapping misspellings to corrections.

Useful output fields

In the job output, you generally only need to analyze the suggested_corrections field, which provides suggestions about using token correction or whole-phrase correction. If the confidence of the correction is not high, then the job labels the pair as “review” in this field. Pay special attention to the output records with the “review” labels. With the output in a CSV file, you can sort by mis_string_len (descending) and edit_dist (ascending) to position more probable corrections at the top. You can also sort by the ratio of correction traffic over misspelling traffic (the corCount_misCount_ratio field) to only keep high-traffic boosting corrections. For phrase misspellings, the misspelled tokens are separated out and put in the token_wise_correction field. If the associated token correction is already included in the one-word correction list, then the collation_check field is labeled as “token correction include.” You can choose to drop those phrase misspellings to reduce duplications. Fusion counts how many phrase corrections can be solved by the same token correction and puts the number into the token_corr_for_phrase_cnt field. For example, if both “outdoor surveillance” and “surveillance camera” can be solved by correcting “surveillance” to “surveillance”, then this number is 2, which provides some confidence for dropping such phrase corrections and further confirms that correcting “surveillance” to “surveillance” is legitimate. You might also see cases where the token-wise correction is not included in the list. For example, “xbow” to “xbox” is not included in the list because it can be dangerous to allow an edit distance of 1 in a word of length 4. But if multiple phrase corrections can be made by changing this token, then you can add this token correction to the list.

Phrase corrections with a value of 1 for token_corr_for_phrase_cnt and with collation_check labeled as “token correction not included” could be potentially-problematic corrections.

Fusion labels misspellings due to misplaced whitespaces with “combine/break words” in the correction_types field. If there is a user-provided dictionary to check against, and both spellings are in the dictionary with and without whitespace in the middle, we can treat these pairs as bi-directional synonyms (“combine/break words (bi-direction)” in the correction_types field). The sound_match and lastChar_match fields also provide useful information.

Job tuning

The job’s default configuration is a conservative, designed for higher accuracy and lower output. To produce a higher volume of output, you can consider giving more permissive values to the parameters below. Likewise, give them more restrictive values if you are getting too many results with low accuracy.

When tuning these values, always test the new configuration in a non-production environment before deploying it in production.


`trainingDataFilterQuery`/Data filter query
See Event types above, then adjust this value to reflect the secondary event for your search application. To query all data, set this to `:`.
`minCountFilter`/Minimum Filtering Event Count
Lower this value to include less-frequent misspellings based on the data filter query.
`maxDistance`/Maximum Edit Distance
Raise this value to increase the number of potentially-related tokens and phrases detected.
`minMispellingLen`/Minimum Length of Misspelling
Lower this value to include shorter misspellings (which are harder to correct accurately).

Query rewrite jobs post-processing cleanup

To perform more extensive cleanup of query rewrites, complete the procedures in Query Rewrite Jobs Post-processing Cleanup.

Query Rewrite Jobs Post-processing Cleanup

The Synonym Detection job uses the output of the Misspelling Detection job and Phrase Extraction job. Therefore, post processing must occur in the order specified in this topic for the Synonym detection job cleanup, Phrase extraction job cleanup, and Misspelling detection job cleanup procedures. The Head-Tail Analysis job cleanup can occur in any order.

Synonym detection job cleanup

Use this job to remove low confidence synonyms.

Prerequisites

Complete this:

AFTER the Misspelling Detection and Phrase Extraction jobs have successfully completed.
BEFORE removing low confidence synonym suggestions generated in the post processing phrase extraction cleanup and misspelling detection cleanup procedures detailed later in this topic.

Remove low confidence synonym suggestions

Use either a Synonym cleanup method 1 - API call or the Synonym cleanup method 2 - Fusion Admin UI to remove low confidence synonym suggestions.

Synonym cleanup method 1 - API call

Open the delete_lowConf_synonyms.json file.

{
"type" : "rest-call",
"id" : "DC_Large_QR_DELETE_LOW_CONFIDENCE_SYNONYMS",
"callParams" : {
    "uri" : "solr://DC_Large_query_rewrite_staging/update",
    "method" : "post",
    "queryParams" : {
    "wt" : "json"
    },
    "headers" : { },
    "entity" : "<root><delete><query>type:synonym AND confidence:[0 TO 0.0005]</query></delete><commit/></root>"
},
"type" : "rest-call",
"type" : "rest-call"
}

REQUEST ENTITY specifies the threshold for low confidence synonyms. Edit the upper range from 0.0005 to increase or decrease the threshold based on your data.

Enter <your query_rewrite_staging collection name/update> in the uri field. An example URI value for an app called DC_Large would be DC_Large_query_rewrite_staging/update.
Change the id field if applicable.
Specify the upper confidence level in the entity field.
The entity field specifies the threshold for low confidence synonyms. Edit the upper range to increase or decrease the threshold based on your data.

Synonym cleanup method 2 - Fusion Admin UI

Log in to Fusion and select Collections > Jobs.
Select Add+ > Custom and Other Jobs > REST Call.
Enter delete-low-confidence-synonyms in the ID field.
Enter <your query_rewrite_staging collection name/update> in the ENDPOINT URI field. An example URI value for an app called DC_Large would be DC_Large_query_rewrite_staging/update.
Enter POST in the CALL METHOD field.
In the QUERY PARAMETERS section, select + to add a property.
Enter wt in the Property Name field.
Enter json in the Property Value field.
In the REQUEST PROTOCOL HEADERS section, select + to add a property.
Enter the following as a REQUEST ENTITY (AS STRING) <root><delete><query>type:synonym AND confidence: [0 TO 0.0005]</query></delete><commit/></root>
REQUEST ENTITY specifies the threshold for low confidence synonyms. Edit the upper range from 0.0005 to increase or decrease the threshold based on your data.

Delete all synonym suggestions

To delete all of the synonym suggestions, enter the following in the REQUEST ENTITY section:<root><delete><query>type:synonym</query></delete><commit/></root>

This entry may be helpful when tuning the synonym detection job and testing different configuration parameters.

Phrase extraction job cleanup

Use this job to remove low confidence phrase suggestions.

Prerequisites

Complete this:

AFTER you complete Synonym detection job cleanup

Remove low confidence phrase suggestions

Use either a Phrase cleanup method 1 - API call or the Phrase cleanup method 2 - Fusion Admin UI to remove low confidence phrase suggestions.

Phrase cleanup method 1 - API call

Open the delete_lowConf_phrases.json file.

{
"type" : "rest-call",
"id" : "DC_Large_QR_DELETE_LOW_CONFIDENCE_PHRASES",
"callParams" : {
    "uri" : "solr://DC_Large_query_rewrite_staging/update",
    "method" : "post",
    "queryParams" : {
    "wt" : "json"
    },
    "headers" : { },
    "entity" : " <root><delete><query>type:phrase AND confidence:[0 TO <INSERT VALUE HERE>]</query></delete><commit/></root>"
},
"type" : "rest-call",
"type" : "rest-call"
}

Enter <your query_rewrite_staging collection name/update> in the uri field. An example URI value for an app called DC_Large would be DC_Large_query_rewrite_staging/update.
Change the id field if applicable.
Specify the upper confidence level in the entity field.
The entity field specifies the threshold for low confidence phrases. Edit the upper range to increase or decrease the threshold based on your data.

Phrase cleanup method 2 - Fusion Admin UI

Log in to Fusion and select Collections > Jobs.
Select Add+ > Custom and Other Jobs > REST Call.
Enter remove-low-confidence-phrases in the ID field.
Enter <your query_rewrite_staging collection name/update> in the ENDPOINT URI field. An example URI value for an app called DC_Large would be DC_Large_query_rewrite_staging/update.
Enter POST in the CALL METHOD field.
In the QUERY PARAMETERS section, select + to add a property.
Enter wt in the Property Name field.
Enter json in the Property Value field.
In the REQUEST PROTOCOL HEADERS section, select + to add a property.
Enter the following as a REQUEST ENTITY (AS STRING) <root><delete><query>type:phrase AND confidence: [0 TO <insert value>]</query></delete><commit/></root>
REQUEST ENTITY specifies the threshold for low confidence phrases. Edit the upper range to increase or decrease the threshold based on your data.

Delete all phrase suggestions

To delete all of the phrase suggestions, enter the following in the REQUEST ENTITY section:<root><delete><query>type:phrase</query></delete><commit/></root>

This entry may be helpful when tuning the phrase extraction job and testing different configuration parameters.

Misspelling detection job cleanup

Use this job to remove low confidence spellings (also referred to as misspellings).

Prerequisites

Complete this:

AFTER you complete Synonym detection job cleanup and Phrase extraction job cleanup

Remove misspelling suggestions

Use either a Misspelling cleanup method 1 - API call or the Misspelling cleanup method 2 - Fusion Admin UI to remove misspelling suggestions.

Misspelling cleanup method 1 - API call

Open the delete_lowConf_misspellings.json file.

{
"type" : "rest-call",
"id" : "DC_Large_QR_DELETE_LOW_CONFIDENCE_MISSPELLINGS",
"callParams" : {
    "uri" : "solr://DC_Large_query_rewrite_staging",
    "method" : "post",
    "queryParams" : {
    "wt" : "json"
    },
    "headers" : { },
    "entity" : "<root><delete><query>type:spell AND confidence:[0 TO 0.5]</query></delete><commit/></root>"
},
"type" : "rest-call",
"type" : "rest-call"
}

Enter <your query_rewrite_staging collection name/update> in the uri field. An example URI value for an app called DC_Large would be DC_Large_query_rewrite_staging/update.
Change the id field if applicable.
Specify the upper confidence level in the entity field.
The entity field specifies the threshold for low confidence spellings. Edit the upper range to increase or decrease the threshold based on your data.

Misspelling cleanup method 2 - Fusion Admin UI

Log in to Fusion and select Collections > Jobs.
Select Add+ > Custom and Other Jobs > REST Call.
Enter remove-low-confidence-spellings in the ID field.
Enter <your query_rewrite_staging collection name/update> in the ENDPOINT URI field. An example URI value for an app called DC_Large would be DC_Large_query_rewrite_staging/update.
Enter POST in the CALL METHOD field.
In the QUERY PARAMETERS section, select + to add a property.
Enter wt in the Property Name field.
Enter json in the Property Value field.
In the REQUEST PROTOCOL HEADERS section, select + to add a property.
Enter the following as a REQUEST ENTITY (AS STRING) <root><delete><query>type:spell AND confidence: [0 TO 0.5]</query></delete><commit/></root>
REQUEST ENTITY specifies the threshold for low confidence spellings. Edit the upper range from 0.5 to increase or decrease the threshold based on your data.

Delete all misspelling suggestions

To delete all of the misspelling suggestions, enter the following in the REQUEST ENTITY section:<root><delete><query>type:spell</query></delete><commit/></root>

This entry may be helpful when tuning the misspelling detection job and testing different configuration parameters.

Head-tail analysis job cleanup

The head-tail analysis job puts tail queries into one of multiple reason categories. For example, a tail query that includes a number might be assigned to the ‘numbers’ reason category. If the output in a particular category is not useful, you can remove it from the results. The examples in this section remove the numbers category.

Prerequisites

The head-tail analysis job cleanup does not have to occur in a specific order.

Remove head-tail analysis query suggestions

Use either a Head-tail analysis cleanup method 1 - API call or the Head-tail analysis cleanup method 2 - Fusion Admin UI to remove query category suggestions.

Head-tail analysis cleanup method 1 - API call

Open the delete_lowConf_headTail.json file.

{
"type" : "rest-call",
"id" : "DC_Large_QR_HEAD_TAIL_CLEANUP",
"callParams" : {
    "uri" : "solr://DC_Large_query_rewrite_staging/update",
    "method" : "post",
    "queryParams" : {
    "wt" : "json"
    },
    "headers" : { },
    "entity" : "<root><delete><query>reason_code_s:(\"number\" \"number spelling\" \"number rare-term\" \"question number other-specific\" \"number others\" \"number other-specific\" \"number other-extra\" \"product number other-specific\" \"product number other-extra\" \"product number spelling\" \"product number others\" \"product number rare-term\" \"product question number\" \"product number re-wording\" \"question number other-extra\" \"number re-wording\")</query></delete><commit/></root>"
},
"type" : "rest-call",
"type" : "rest-call"
}

Enter <your query_rewrite_staging collection name/update> in the uri field. An example URI value for an app called DC_Large would be DC_Large_query_rewrite_staging/update.
Change the id field if applicable.

Head-tail analysis cleanup method 2 - Fusion Admin UI

Log in to Fusion and select Collections > Jobs.
Select Add+ > Custom and Other Jobs > REST Call.
Enter remove-low-confidence-head-tail in the ID field.
Enter <your query_rewrite_staging collection name/update> in the ENDPOINT URI field. An example URI value for an app called DC_Large would be DC_Large_query_rewrite_staging/update.
Enter POST in the CALL METHOD field.
In the QUERY PARAMETERS section, select + to add a property.
Enter wt in the Property Name field.
Enter json in the Property Value field.
In the REQUEST PROTOCOL HEADERS section, select + to add a property.

Enter the following as a REQUEST ENTITY (AS STRING)

<root><delete><query>reason_code_s:("number" "number spelling" "number rare-term" "question number other-specific" "number others" "number other-specific" "number other-extra" "product number other-specific" "product number other-extra" "product number spelling" "product number others" "product number rare-term" "product question number" "product number re-wording" "question number other-extra" "number re-wording")</query></delete><commit/></root>

Delete all head-tail suggestions

To delete all of the head-tail suggestions, enter the following in the REQUEST ENTITY section:<root><delete><query>type:tail</query></delete><commit/></root>

This entry may be helpful when tuning the head-tail job and testing different configuration parameters.

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Release Notes

​1. Create a job

​2. Configure the job

​Required configuration

​Event types

​Spell check documents

​Use a custom dictionary

​Example configuration

​3. Run the job

​4. Analyze job output

​5. Use spell correction results

​Useful output fields

​Job tuning

​Query rewrite jobs post-processing cleanup

​Configuration properties

1. Create a job

2. Configure the job

Required configuration

Event types

Spell check documents

Use a custom dictionary

Example configuration

3. Run the job

4. Analyze job output

5. Use spell correction results

Useful output fields

Job tuning

Query rewrite jobs post-processing cleanup

Configuration properties